An active material (an alloy-based active material) containing a metal such as Si, the metal being able to form an alloy with Li, has a large theoretical capacity per volume compared to carbon-based anode active materials. Therefore, a lithium ion battery using such an alloy-based active material in its anode, has been proposed.
Patent Literature 1 discloses a negative electrode mixture for a secondary battery, the mixture comprising, as a negative electrode active material powder, an alloy-based active material having an average particle diameter of 10 μm or less. Patent Literature 1 also discloses an all-solid lithium ion battery comprising an anode layer that contains the negative electrode active material powder.
Patent Literature 1: Japanese Patent Application Laid-Open No. 2013-69416
However, the all-solid-state lithium ion secondary battery as disclosed in Patent Literature 1 which uses an alloy-based active material as an anode active material, shows a low capacity retention rate when it repeats charge-discharge cycles.